Selective glass batching methods for improving melting efficiency and reducing gross segregation of glass batch components

ABSTRACT

A method of controlling reaction paths of glass batch components added to a resident glass melt is provided, including the steps of providing a plurality of raw material batch components according to a batch recipe, selectively combining a portion of the batch components into a first combination material having a melting temperature in a range of 60 to 90% of a resident melt temperature (K) and a viscosity 3  a melt viscosity/100, and selectively combining another portion of the batch components into a second combination material having a reaction temperature in a range of 60 to 100% of the resident melt temperature, the second combination material being capable of forming an intermediate compound via a solid state reaction before reacting with the glass melt. The first and second combination materials and any remaining batch components are mixed and introduced into a glass melter.

FIELD OF THE INVENTION

The present invention relates to selective batching methods in generaland more particularly, to selectively combining particular constituentsof a glass batch composition before introducing the batch to the melt inorder to reduce the tendency for gross segregation of batch componentsin the melt and to improve melting efficiency by controlling thermalreaction paths.

BACKGROUND OF THE INVENTION

Conventional glass batching processes are illustrated as a flow diagramin FIG. 1. Typical glass batching usually involves transferring rawmaterials directly from storage silos into a weigh hopper, weighing theraw materials according to a weight percent (wt %) batch recipe, addinga specified amount of cullet, and mixing the raw batch and the cullet ina large scale mixer. In some cases, the mixer itself functions as afinal check-scale for the batch recipe. From the mixer, the mixed batchmaterials are transferred to one or more hoppers positioned adjacent theend of a glass furnace (melter) where the mixed batch is introduced intothe melting tank. Similar batching techniques are nearly universallyemployed in various glass producing industrial settings, includingcontainer glass, fiber-glass, and float glass manufacturing facilities.

After the mixed batch is added to the furnace (melter), uncontrolledreactions are allowed to occur in melter at various temperatures, bothamong the batch raw material components and between the batch rawmaterial components and resident melt, until a substantially homogenousmelt is eventually achieved. The time required for sufficient melting,homogenization and fining is related to the total residence time, or thetime that the melt resides within the melter tank before being formedinto the desired glass product.

FIG. 2 is a schematic illustration showing the reaction paths that theraw material batch components typically follow when reacting with eachother and with the melt already present in the furnace, and FIG. 3 is aschematic illustration showing the conventionally uncontrolled meltingstages as the newly added batch melts. See also, for example, F. E.Woolley, “Melting/Fining,” Ceramics and Glasses, Engineered MaterialsHandbook, Vol. 4, ASM International, 1987, pp. 386-393, the entirety ofwhich is incorporated herein by reference.

That is, once the batch is introduced to the furnace, several reactionstake place that almost immediately segregate the batch. In float glassproduction, for example, sodium carbonate (Na₂CO₃), calcium carbonate(CaCO₃), sodium sulfate (Na₂SO₄) and quartz (SiO₂) are the most commonlyused major raw materials. When water has not been added in an effort toreduce batch segregation in the storage hopper, the first reaction isusually the formation of a eutectic liquid by the reaction of Na₂CO₃ andCaCO₃ at a temperature of around 785° C.

As shown in FIG. 2, Na₂CO₃ and CaCO₃ react along reaction Path 1,creating a low viscosity eutectic liquid with a quantity of un-reactedCaCO₃. This low viscosity eutectic liquid reacts with residual CaCO₃ andquartz along reaction Path 2 to eventually achieve the overallcomposition of the glass dictated by the batch recipe. An example of atypical float glass composition is approximately 73.5 wt. % SiO₂, 12.3wt. % CaO, and 14.2 wt. % Na₂O.

Similar reactions are observed between Na₂CO₃, CaCO₃, and Na₂SO₄. Inthis case, the eutectic liquid is composed of molten salts having a verylow viscosity. That is, the eutectic liquid flows easily, and exhibitsflow properties similar to those exhibited by water, which has aviscosity in a range of 1 to 4 mPa.s, or 1 to 4 centipoise. The eutecticliquid reacts with the quartz to eventually provide a homogeneous glassof the desired composition. The formation of this eutectic liquid,however, can increase the tendency for batch segregation and effectivelyreverse the efforts of batch mixing.

Similar reactions occur in container glass compositions, and in the caseof fiber-glass production, borates exhibit similar problems in theinitial stages of melting. This segregation process leads to theformation of large-scale domains, or agglomerates, of nearly pure silicathat then require excessively long residence times for dissolution intothe surrounding liquid melt. This initial segregation then requiresre-homogenization within the glass tank prior to forming.

Direct evidence of “de-mixing” can be seen in a glass tank during themelting process. Agglomerations (scaled on the order of cm in length) ofbatch raw materials, commonly referred to in the industry as batch logs,can be seen in various states of melting in the glass tank. Moreover,the phenomenon of large-scale batch segregation in the melter tank iscommonly seen in finished glass in the form of defects such as stones,which are mostly composed of undissolved quartz; seeds, which arebubbles that are not liberated from the melt during fining; and cordlines, which are optical distortions caused by local differences incomposition. These defects are direct evidence of off-composition glassdue to batch de-mixing or incomplete re-mixing that decrease the overallmaterial efficiency and reduce the quality of the final product.Industrial observations are further supported by technical publications,which also recognize that batch segregation is commonly observed incommercial production. Despite the fact that batch segregation in theglass tank and the potential defects that can result therefrom arerecognized in the industry, and despite a long felt need to reduce thisundesirable behavior and improve melting efficiency and overall quality,the glass industry has not yet successfully addressed these issues witha viable commercial solution.

As mentioned above, material efficiency in glass making is related toreducing losses due to defects such as stones, seeds, and cord lines.Stones are silica particles or agglomerates that have not fully reactedwith the melt. This type of stone can be reduced by reducing segregationof refractory silica from flux materials. Seeds, which are bubbles thatresult from incomplete fining, can be reduced by maximizing theevolution of volatiles early in the melting process and by reducing airtrapped in pore spaces. While cullet from some defective glass can berecycled through the process (though glass with stones cannot berecycled), it is more efficient to reduce in-house cutlet from defectiveglass.

In large scale commercial glass production (e.g., float glass, containerglass, and fiber-glass) where the melting tank volumes are considerablygreater (accommodating volumes on the order of tons of molten glass), insitu melt mixing is accomplished by convection currents within the tankand by the movement of evolved gases from decomposition of rawmaterials. While some mixing and fining is required to remove gaseousbubbles, the expensive and energy intensive processes to improve themixing of the molten batch can also be attributed to large scalesegregation of batch materials.

Considering that physical mixing is but a minor factor, the efficiencyof the melting process is therefore directly related to diffusion orreactions at the quartz-liquid interface. Quartz dissolution is limitedby the initial reaction of quartz with the low viscosity eutecticliquid. As the melting progresses, the quartz interacts with a liquidthat is steadily increasing in silica content and subsequently,viscosity. Therefore, high temperatures are needed within the meltingtank to ensure reasonable diffusion rates and reasonable homogeneity. Asmentioned above, the residence time of the material in a tank isdetermined by the time it takes for the batch materials to completelymelt and for the resulting liquid to homogenize. In a continuousproduction situation, the mass of molten glass in the furnace is heldconstant, and commercially, the minimum mean residence time is of theorder of 24 hours of production for container furnaces and 72 hours forfloat glass furnaces with roughly half of this time devoted to melting,with the other half devoted to fining.

One attempt to improve the batch melting process involved reducing theaddition of carbonate and quartz in the raw (unmixed) form. Experimentswere conducted using synthetic diopside (CaO.MgO.2SiO₂) instead of amixture of CaCO₃, MgCO₃, and quartz. The results showed that the timerequired to completely dissolve the original batch (i.e., the batch freetime) was reduced depending on temperature, and there was also areduction in fining time. These improvements were attributed to areduction in the amount of quartz that needed to be dissolved. See, forexample, C. C. Tournour and J. S. Shelby, “Effect of Diopside andWollastonite on the Melting of Soda-Lime-Silicate Glasses,” CeramicEngineering and Science Proceedings, edited by J. Kieffer, AmericanCeramic Society, 21 [1], 263-273 (2000), the entirety of which isincorporated herein by reference.

It is also conventionally believed that melting is promoted by keepingthe viscosity low. As described above, however, the uncontrolledproduction of low viscosity liquids during the melting processcontributes to undesirable batch segregation. Although a melt thatfosters lower viscosities overall may improve quartz dissolution anddiffusion rates during melting, these benefits can only be achievedafter the highest melting point batch components are sufficiently meltedand any batch agglomerates are fully reacted in the melt. Thus, in orderto improve melting efficiency and reduce the above-described problemsassociated with de-mixing and segregation, substantial improvements withrespect to controlling the glass batch melting behavior are desired.

Another problem with conventional glass making technology lies in theamount of energy required to maintain a continuous glass meltingoperation, and the environmental impact of the use of fossil fuel toprovide this energy. Fuel can constitute 25-30% of the cost ofmanufacturing float glass. The volatility of fuel prices can, of course,at times increase this proportion without warning.

Nationwide, the U.S. glass industry uses in excess of 250 trillion BTUannually to produce approximately 21 million tons of glass products;approximately 80% of this energy is supplied by natural gas. Melting oneton of glass should theoretically require only about 2.2 million BTU,but in reality it can range from 4.7 to 6.9 million BTU per ton due tolosses and inefficiencies. Because 80% or more of the overall energyused in container glass, fiber-glass, and float glass manufacturing isneeded to operate the melting and fining operations, an energy reductionin glass manufacturing through more efficient melting would bedesirable. For example, if a float glass plant producing 400 tons/day offlat glass runs 365 days/year, even the most efficient natural gas-firedplant (4.7 million BTU/ton) consumes approximately 686 billion BTU/year,or 686 million cubic feet of natural gas. See, for example, U.S.Department of Energy, Office of Industrial Technology, 1997, and“Integrated Pollution Prevention Control (IPPC),” Reference Document onBest Available Practices in the Glass Manufacturing Industry, EuropeanCommission, Institute for Prospective Technological Studies, Seville,2000, the entireties of which are incorporated herein by reference.

Pollution prevention and the considerable costs associated withregulatory compliance, as well as improving the overall energy andmaterial efficiency are critical for reducing the negative environmentalimpact of glass manufacturing and for making glass manufacturing moreeconomically competitive. For example, a typical float glass plant mustspend an average of $2 million dollars for new environmental controlsystems and about 2.5% of total manufacturing costs on compliance. (See,for example, “Glass: A Clear Vision for a Bright Future,” U.S.Department of Energy, 1996, the entirety of which is incorporated hereinby reference). Thus, a reduction in 10% of the natural gas use in atypical float plant would result in a savings of approximately $285,000per year in natural gas (assuming $5/MMBtu). Moreover, reductions incompliance costs associated with additional chemical treatments andoperational implementations aimed at reducing pollutant emissions fromcombustion reactions could also be realized in conjunction with areduction in the amount of fuel consumed.

Air pollutants emitted from glass industry include: 1) Nitrogen oxides(NO_(x)) 2) Sulfur oxides (SO_(x)) 3) Carbon monoxide (CO) 4) CarbonDioxide (CO₂)Fossil fuels used for combustion are the typically the sources of NO_(x)and some CO_(x). The decomposition of carbonate and sulfate rawmaterials contributes CO_(x) and SO_(x) emissions, respectively.Reducing the residence time, however, reduces the amount of fuel burnedper unit of glass produced and improves energy efficiency, which alsofosters reduced amounts of emissions such as NO_(x) and fuel-derived CO₂and CO per unit of glass produced.

Residence time is related to the time required to fully melt all of thebatch components, and is particularly dependent upon the amount ofhigh-melting point batch components (e.g., silica) in the batch recipe.Although it would be desirable to eliminate free quartz as a rawmaterial additive due to its slow reactivity and high melting point,quartz remains an abundant and economical source of silica, which is amajor component of many commercial glass systems. Therefore, it would bemore desirable to reduce the amount of free quartz added by obtaining aportion of the silica from selectively combined binary or ternarymixtures that are either pelletized together, pre-reacted or pre-meltedprior to batching and being introduced into the resident melt, which isheretofore unknown in the glass industry.

Thus, it would be desirable to provide a method for controlling themelting behavior (i.e., reaction paths) of glass batch components withina resident melt to improve melting efficiency, such that the improvedmelting efficiency enables a decrease in energy usage, reduces the needfor chemical fining agents that contribute to air pollutants and rawmaterial cost, decreases pollution while ultimately producing higherquality, lower cost glass products and reduces the occurrence of batchde-mixing and segregation in early melting stages.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the drawbacksassociated with the conventional glass batching and melting methods.Particularly, it is an object of the present invention to provide amethod for selectively pre-combining certain components of a glass batchrecipe prior to introducing the overall batch composition into a furnacemelting tank to control the melting reactions (i.e., reaction paths)within the tank in order to improve melting efficiency.

In conjunction with improved melting efficiency, it is also an object ofthe present invention to facilitate decreased energy usage, reduce theneed for chemical fining agents that contribute to air pollutants andraw material cost, decrease pollution and ultimately produce higherquality, lower cost glass products, and reduce gross segregation of rawmaterial batch constituents during melting.

According to one embodiment of the present invention, a method ofcontrolling the reaction paths of glass batch components added to aglass melt residing in a glass melter is provided. The glass melt has amelt viscosity (η_(m)) at a resident melt temperature (T_(m)), measuredon an absolute temperature scale (i.e., Kelvin). The method includes thesteps of providing a plurality of raw material batch components inamounts according to a batch recipe, wherein the plurality of rawmaterial batch components include at least one of a glass-formermaterial and at least one of a modifier (flux) material. A first portionof the plurality of raw material batch components is selectivelycombined to provide a first combination material having a meltingtemperature which is in a range of 60 to 90% of the resident melttemperature T_(m) and a viscosity at the melting temperature that isgreater than or equal to the melt viscosity η_(m)/100. A second portionof the plurality of raw material batch components is also selectivelycombined to provide a second combination material having a reactiontemperature in a range of 60 to 100% of the resident melt temperature,such that the second combination material is capable of forming anintermediate compound via a solid state reaction prior to reacting withthe glass melt. The first combination material, the second combinationmaterial and any remaining portion of the plurality of raw materialbatch components are mixed together to form a batch mixture, and thebatch mixture is introduced into the glass melter.

The first combination material can be provided in various forms. Forexample, according to one aspect of the first embodiment of the presentinvention, the first combination material can be provided as a pluralityof discrete reaction members formed by pelletizing the first combinationmaterial prior to the introducing step, wherein reaction member has acomposition based on the first combination material. Alternatively, thefirst combination material can be provided as a pre-reacted materialformed by pre-reacting the first combination material to a temperatureproximate a specific reaction temperature of the first combinationmaterial, cooling the pre-reacted first combination material, andgrinding the pre-reacted first combination material to form a pluralityof pre-reacted particulates prior to the introducing step. In this case,each of the plurality of pre-reacted particulates has a compositionbased on the first combination material. According to yet anotheralternative, the first combination material can be provided as a fritformed by heating the first combination material to a temperatureproximate a melting temperature of the first combination material,melting the first combination material and quenching the firstcombination material to form the frit prior to the introducing step. Inthis case, as with the discrete reaction members and the pre-reactedparticulates, the frit has a composition according to the firstcombination material.

Similarly, the second combination material can be provided in a varietyof forms. For example, according to another aspect of the firstembodiment of the present invention, the second combination material canbe provided as a plurality of discrete reaction members formed bypelletizing the second combination material prior to the introducingstep, wherein the reaction member has a composition based on the secondcombination material. Alternatively, the second combination material canbe provided as a pre-reacted material formed by pre-reacting the secondcombination material to a temperature proximate a specific reactiontemperature of the second combination material, cooling the pre-reactedsecond combination material, and grinding the pre-reacted secondcombination material to form a plurality of pre-reacted particulatesprior to the introducing step. In this case, each of the plurality ofpre-reacted particulates has a composition based on the secondcombination material. According to yet another alternative, the secondcombination material can be provided as a frit formed by heating thesecond combination material to a temperature proximate a meltingtemperature of the second combination material, melting the secondcombination material and quenching the second combination material toform the frit prior to the introducing step. In this case, as with thediscrete reaction members and the pre-reacted particulates, the frit hasa composition according to the second combination material.

The plurality of raw material batch components of the present inventioncan also include an intermediate material, in addition to the at leastone glass-former material and the at least one modifier material. Itshould be noted that since the present invention can be applied equallywell for any type of glass manufacturing, the exact composition of thecombination materials will vary according to the batch recipe used inthe particular field of glass making. For example, typical soda limesilicate float glass compositions do not include an intermediatematerial, such as alumina or zirconia, and instead include a pluralityof modifiers, such as sodium and calcium, in various carbonate and oxideforms, depending upon the raw materials from which the are derived.

For glass compositions that include an intermediate material, the firstcombination material can include at least a portion of the intermediatematerial and at least a portion of at least one of the modifiermaterials, and the second combination material can include at least aportion of at least one of the glass-former material and at least aportion of at least one of the modifier material. Additionally, thesecond combination material can include at least a portion of theintermediate material and at least a portion of at least one of themodifier materials, and the first combination material can at least aportion of at least one of the glass-former material and at least aportion of at least one of the modifier material. Ternary sub-systemscreated by selective batching methods according to the presentinvention, rather than binary sub-systems, are particularly applicablewhen dealing with glasses containing significant levels of alumina.

Although the exact composition of the combination materials can varyaccording to the particular application, the general combinations of rawmaterial batch components according to the present invention remainsconstant. That is, the first combination material can include at least aportion of at least one of the glass-former materials and at least aportion of at least one of the modifier materials, and the secondcombination material can include at least a portion of at least one ofthe glass-former materials and at least a portion of another of themodifier materials.

The term “glass-former material” or glass-former refers to materialswhich have a M_(x)O_(y) oxide form (where x=1 or 2; y=1-5) and a singleO-M bond strength on the order of 80-120 kcal. The glass-former materialcan be included as a batch component raw material in its oxide form, orcan be the product of calculated decomposition reactions of other batchcomponent raw materials, such as carbonates, hydroxides, chlorides,nitrates, sulfides, or multi-component industrial minerals.Glass-formers according to the present invention can include, forexample, oxide forms of Be, Ge, Si, P, and B.

The term “intermediate material” or intermediate refers to materialswhich have a M_(x)O_(y) oxide form and a single O-M bond strength on theorder of 60-75 kcal. The intermediate material can be included as abatch component raw material in its oxide form, or can be the product ofcalculated decomposition reactions of other batch component rawmaterials, such as carbonates, hydroxides, chlorides, nitrates,sulfides, or multi-component industrial minerals. Intermediatesaccording to the present invention can include, for example, oxide formsof Mn, Mg, Zr, Be, Fe, Al and Ti.

The term “modifier material” refers to materials which have a M_(x)O_(y)oxide form and a single O-M bond strength on the order of 10-60 kcal,and which substantially perform as fluxing materials during thermalreactions. The modifier material can be included as a batch componentraw material in its oxide form, or can be the product of calculateddecomposition reactions of other batch component raw materials, such ascarbonates, hydroxides, chlorides, nitrates, sulfides, ormulti-component industrial minerals. Intermediates according to thepresent invention can include, for example, oxide forms of K, Na, Li,Ba, Pb, Sr, Ca, Mg, Mn, and Fe.

It should be noted that, according to the present invention, modifiersshould not be selectively combined with other modifiers in the absenceof a glass-former or an intermediate, due to the reactive nature (i.e.,fluxing behavior) of modifiers. That is, a combination material formedfrom a modifier-modifier selective combination would not reduce theoccurrence of batch segregation due to modifiers' tendency to form lowviscosity eutectic liquid at lower temperatures.

It should also be noted that, according to the present invention,intermediates and glass-formers should not be selectively combinedwithout a modifier to reduce the melting temperature of the combinationmaterial. That is, an intermediate-glass-former selective combinationwould not yield any significant benefits with respect to narrowing themelting temperature range of the batch components and would not exhibitthe desired viscosity in the temperature range of the present invention.Nor would beneficial solid state reactions occur in lieu of melting.Instead, the combination material would simply require a longerresidence time for melting and homogenization with the resident melt,which decreases the overall melting efficiency.

As mentioned above, there are three preferred forms in which eachcombination material can be stabilized prior to being mixed with othercombination materials and any remaining portions of the batch (e.g.,cullet or previously uncombined weight percentages of the glass-formers,modifiers or, if included, intermediates). The present inventionprovides method for selectively batching the raw material batchcomponents wherein the first combination material and the secondcombination material comprise the same or different forms.

For example, according to one aspect of the first embodiment of thepresent invention, the first combination comprises a plurality ofdiscrete reaction members and the second combination material comprisesa plurality of discrete reaction members. Thus, in this case, each ofthe first and second combination materials are selectively pre-mixed andpelletized to form a pelletized feed stock prior to being mixed witheach other and the remaining batch components and being added to themelter. Additionally, according to another aspect of the firstembodiment of embodiment of the present invention, the first combinationmaterial comprises a plurality of discrete reaction members and thesecond combination material comprises a pre-reacted material. Further,according to yet another aspect of the first embodiment of embodiment ofthe present invention, the first combination material comprises aplurality of discrete reaction members and the second combinationmaterial comprises a frit.

The present invention also provides that the first combination materialcomprises a pre-reacted material and the second combination materialcomprises a plurality of discrete reaction members. Alternatively, thepresent invention provides that the first combination material comprisesa pre-reacted material and the second combination material comprises apre-reacted material. Thus, in this case, each of the first and secondcombination materials are selectively pre-mixed and pre-reacted andground to form a particulate feed stock material prior to being mixedwith each other and the remaining batch components and before beingadded to the melter. Further, the present invention provides that thefirst combination material comprises a pre-reacted material and thesecond combination material comprises a frit.

Further, according to another aspect of the first embodiment of thepresent invention, the first combination material comprises a frit andthe second combination material comprises a plurality of discretereaction members. Alternatively, the present invention provides that thefirst combination material comprises a frit and the second combinationmaterial comprises a pre-reacted material. Moreover, according to yetanother aspect of the first embodiment of the present invention, thefirst combination material comprises a frit and the second combinationmaterial comprises a frit. Thus, in this case, each of the first andsecond combination materials are selectively pre-mixed and pre-meltedand quenched to form a frit feed stock material prior to being mixedwith each other and the remaining batch components and before beingadded to the melter.

Selectively batching raw materials into mixtures (i.e., the firstcombination material of the first embodiment) that form higher viscosity“endpoints,” to control the melting sequence and consequently theviscosity of the molten phase(s), instead of simply mixing all of thebatch components together prior to charging, controls the reaction pathswithin the melter, rather than allowing the melting process to dictatethe composition of the melt at various stages. That is, if all of thebatch constituents possessed melting points within a narrow temperaturerange, more uniform melting could be achieved, segregation (regardlessof magnitude) would be limited, and the time required for homogenizationsubstantially reduced. Furthermore, if de-mixing is eliminated,diffusion distances are shortened and batch free time would bedramatically reduced.

Selectively batching raw materials into a mixture (i.e., the secondcombination material of the first embodiment) that is capable of formingan intermediate compound that will react in a series of solid statereactions with the glass melt and the other components of the glassbatch rather than melting, even at temperatures approaching the residentglass melt temperature, prevents the formation of low viscosity eutecticcompounds that can increase the tendency for batch segregation. Further,since the intermediate compound does not itself melt per se, theabove-mentioned viscosity considerations are rendered moot in view ofthe solid-state reactions that instead yield in a glass melt having adesired composition with improved melting efficiency, for example, byreducing the tendency for the segregation complications that reducemelting efficiency.

The selective batching techniques according to the present inventionalter the reaction sequence during the melting process to createintermediate reaction products that are then more easily reacted witheach other, improve melting efficiency, and thus significantly reducethe overall energy needs and time required to form a homogeneous melt.The tendency for large scale segregation can also be reduced (i.e.,substantially eliminated), thus providing shorter diffusion distances.This, in turn, eliminates the need for downstream mechanical mixing ofthe melt, such as mechanical stirring, or other physical implementationsto improve melting efficiency, for example, bubblers designed toincrease the heat capacity of the melt. The time required for sufficientmelting and homogenization is substantially reduced, and fining timescan be reduced, as well. In lieu of reducing the residence time,however, it is also possible to allow for additional fining time in thecurrent furnace setup, that is, if the overall residence time ismaintained.

Controlling the reaction paths of batch components to improve meltingefficiency reduces the residence time of material in the glass tank andreduces the batch-free time, as well. This, in turn, reduces the amountof energy required per unit of glass during production. For example, ifresidence time of material in the tank can be reduced by 10% to 20%, ahypothetical float glass plant could reduce the annual natural gas useby 57 to 114 million cubic foot (for the most efficient 4.7 million BTUper ton), assuming that 83% of the total energy is used for melting. Ona nationwide scale of all glass manufacturing, a 10% reduction inresidence time could result in a savings of 20 trillion BTU or 16billion cubic foot of natural gas (assuming 250 trillion BTU, 80%natural gas usage and 1×10³ BTU per cubic foot natural gas).

Sulfur oxides are a decomposition product of saltcake (sodium sulfate)that is added to the batch as a fining agent. The improved meltingefficiency attributed to the present invention reduces the need forfining agents such as saltcake (Na₂SO₄) and thus, directly reduce SO_(x)emissions. Reducing these and other harmful emissions reduces the needfor and costs of compliance (e.g., implementation measures and/orcompliance failure fines) with environmental emission standards.

According to a second embodiment of the present invention, a method ofcontrolling the reaction paths of glass batch components added to aglass melt residing in a glass melter is provided. The glass melt has amelt viscosity η_(m) at a resident melt temperature T_(m), measured onan absolute temperature scale (i.e., Kelvin). The method includes thesteps of providing a plurality of raw material batch components inamounts according to a batch recipe, wherein the plurality of rawmaterial batch components include at least one of a glass-formermaterial and at least one of a modifier material. The method alsoincludes the steps of selectively combining a first portion of theplurality of raw material batch components to provide a firstcombination material having a melting temperature which is in a range of60 to 90% of the resident melt temperature T_(m) and a viscosity at themelting temperature which is greater than or equal to the melt viscosityη_(m)/100, and mixing the first combination material and any remainingportion of the plurality of raw material batch components to form abatch mixture. The batch mixture is then introduced into the glassmelter.

According to this second embodiment of the present invention, the methodfurther includes a step of selectively combining a second portion of theplurality of raw material batch components to provide a secondcombination material having a melting temperature which is in a range of60 to 90% of the resident melt temperature T_(m) and a viscosity at themelting temperature that is greater than or equal to the melt viscosityη_(m)/100. The second combination material is mixed with the firstcombination material and any remaining portion of the plurality of rawmaterial batch components to form a batch mixture, which is thenintroduced into the glass melter.

It should be noted that this embodiment of the present invention isprimarily directed to selectively combining the raw material batchcomponents to narrow the melting point range of the added batch and tocontrol the viscosity of the added batch during melting to improve themelting efficiency and prevent batch segregation, as described abovewith respect to the first embodiment.

Different combinations of raw material batch components to form thefirst and second combination materials according to the secondembodiment of the present invention are similar to those described abovewith respect to the first embodiment, and further redundant descriptionthereof is therefore omitted. Likewise, the different forms in which thefirst and second combination materials according to the secondembodiment of the present invention can be stabilized prior to beingmixed with each other and with any remaining batch components aresimilar to those described above with respect to the first embodiment,and further redundant description thereof is therefore omitted.

According to a third embodiment of the present invention, a method ofcontrolling the reaction paths of glass batch components added to aglass melt residing in a glass melter is provided. The glass melt has amelt viscosity η_(m) at a resident melt temperature T_(m), measured onan absolute temperature scale (i.e., Kelvin). The method includes thesteps of providing a plurality of raw material batch components inamounts according to a batch recipe, wherein the plurality of rawmaterial batch components including at least one of a glass-formermaterial and at least one of a modifier material. The method alsoincludes the steps of selectively combining a first portion of theplurality of raw material batch components to provide a firstcombination material having a reaction temperature in a range of 60 to100% of the resident melt temperature, such that the first combinationmaterial is capable of forming an intermediate compound via a solidstate reaction prior to reacting with the glass melt and mixing thefirst combination material and a remaining portion of the plurality ofraw material batch components to form a batch mixture. The batch mixtureis then introduced into the glass melter.

According to this third embodiment of the present invention, the methodfurther includes a step of selectively combining a second portion of theplurality of raw material batch components to provide a secondcombination material having a reaction temperature in a range of 60 to100% of the resident melt temperature, such that the second combinationmaterial is capable of forming an intermediate compound via a solidstate reaction prior to reacting with the glass melt. The secondcombination material is mixed with the first combination material andany remaining portion of the plurality of raw material batch componentsto form a batch mixture, which is then introduced into the glass melter.

It should be noted that this third embodiment of the present inventionis primarily directed to selectively combining portion of the rawmaterial batch into a combination material that is capable of forming anintermediate compound via a solid state reaction with the glass meltwithin a certain temperature range of the resident melt temperature toimprove the melting efficiency and prevent batch segregation, asdescribed above with respect to the second combination material of thefirst embodiment.

Different combinations of raw material batch components to form thefirst and second combination materials according to the third embodimentof the present invention are similar to those described above withrespect to the first embodiment, and further redundant descriptionthereof is therefore omitted. Likewise, the different forms in which thefirst and second combination materials according to the third embodimentof the present invention can be stabilized prior to being mixed witheach other and with any remaining batch components are similar to thosedescribed above with respect to the first embodiment, and furtherredundant description thereof is therefore omitted.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the presentinvention, reference should be made to the following drawings, in which:

FIG. 1 is a flow diagram illustrating conventional glass batchingtechniques;

FIG. 2 is a schematic illustration of the conventional batch reactionpaths for a typical commercial float glass composition;

FIG. 3 is a schematic diagram illustrating a conventional batch reactionprocess;

FIG. 4 is a flow diagram illustrating a first embodiment of theselective glass batching method according to the present invention;

FIG. 5 is a flow diagram illustrating a second embodiment of theselective glass batching method according to the present invention;

FIG. 6 is a flow diagram illustrating a third embodiment of theselective glass batching method according to the present invention;

FIG. 7 is a is a ternary phase diagram of a selectively combined glassbatch sub-system according to the example based on a commercial floatglass composition; and

FIG. 8 is a flow diagram illustrating the selective batching methodaccording to the example.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, selective blending of particularcombinations of batch raw materials according to the overall batchrecipe is performed (hereinafter also referred to as “selectivebatching”), rather than the complete blending of the entire batchcomposition prior to introduction to a glass melter (e.g., furnace tank)having molten glass (hereinafter referred to as “melt”) residingtherein. Selectively batching in this manner provides intermediate batchreaction products whose thermal characteristics (i.e., melting point)and rheological properties (i.e., viscosity) or high temperaturereaction behaviors improved melting efficiency and reduce the occurrenceof batch constituent segregation (regardless of magnitude) during theinitial melting stages.

As shown in the flow diagram in FIG. 4, one embodiment of the presentinvention is directed to narrowing the melting point range of the batchconstituents by selectively combining a first portion of the batchcomponents such that the selective combination exhibits the desiredTheological properties (i.e., increased viscosity) in the molten phaseformed during the narrowed melting point range. Additionally, a secondportion of the batch components are selectively combined such that theselective combination has a specific reaction temperature range whereinan intermediate compound is formed via a solid state reaction betweenthe combination and the resident melt.

Stabilizing the form of the new combination form of the selectivelycombined batch components can be accomplished in various ways whichthemselves have various levels of energy requirements: selectively batchand pelletize to form small “reaction members” that react initially toform an intermediate reaction product; pre-react selective batchcomponents to form an intermediate feedstock; or pre-melt selectivebatch components as an intermediate feedstock.

FIG. 4 shows that the batch recipe calls for a specified wt % ofglass-former A, modifier B and modifier C. At least a portion ofglass-former A and at least a portion of modifier B are selectivelycombined on a wt % basis to form a first combination material AB thatwill have a melting temperature T_(AB) in a range of 60-90% of theresident melt temperature T_(m) and a viscosity η_(AB)≧the resident meltviscosity η_(m)/100. Preferably, η_(AB) is in a range of 150 centipoiseto 15,000 centipoise, although viscosities exceeding 15,000 centipoiseare not outside the scope of the present invention. The preferredviscosity η_(AB) of the first combination material can also be expressedas being at least 1% of η_(m). It should be noted that the viscositiesof the above-mentioned conventionally encountered low viscosity eutecticliquids that contribute to batch segregation (and are thus to beavoided) are considerably less than 1% of the viscosity of the residentmelt. For example, the viscosity of the eutectic liquid formed by thereactions between CaCO₃ and Na₂CO₃ is approximately 0.03% of theviscosity of the resident melt.

It should also be noted that although T_(m) is preferably expressed interms of Kelvin (i.e., an absolute temperature scale), T_(m) can also beexpressed by other units for measuring temperature, for example, degreesCelcius (°C.). Although the different temperature scales can be comparedto one another using common conversion factors, for purposes ofestablishing the relationship between the resident melt temperature andthe temperature ranges over which the selectively combined batchcomponents either melt or react according to the present invention, theabsolute temperature scale is preferred.

Similarly, at least another portion of glass-former A and at least aportion of modifier C are selectively combined on a wt % basis to form asecond combination material AC that will have a reaction temperatureT_(AC) in a range of 60-100% of the resident melt temperature T_(m) suchthat melt homogenization and diffusion will occur via solid statereactions rather than by melting the second combination material AC.Each of the first AB and second AC combination materials are thenpelletized.

It is important to note that the present invention does not involvepelletizing as a batching step per se, rather, pelletized batchingtechniques are simply one of three methods used to keep the selectivelybatched components together in the form of the respective combinationmaterials as they are introduced into the furnace. Although batchpelletizing is known in the art, typical pelletizing practices relate topelletizing the entire batch, rather than selectively pelletizingportions of the batch in specific compositional ratios in order tocontrol the melting reactions in the tank. Technical publications andindustrial practices strongly support that selective pelletizing ofparticular batch components has been unheard of heretofore.

Pelletized AB, pelletized AC, and any remaining portions of A, B and/orC are then mixed in a mix hopper, for example, and then added to amelter. It should also be noted that AB and AC can also be pre-reactedor pre-melted. Controlled reactions occur in the melter at varioustemperatures between the selectively combined batch raw materialcomponents AB and AC and the resident melt, until a substantiallyhomogenous melt is eventually achieved. Although the traditionaluncontrolled reactions may still occur on a limited level between theportions of the batch components A, B and C that were not selectivelycombined, these reactions are proportionally reduced and do notsignificantly reduce the improved melting efficiency, for example, byforming low viscosity phases within the melt which cause segregation.

As shown in the flow diagram in FIG. 5, another embodiment of thepresent invention is directed to narrowing the melting point range ofthe batch constituents by selectively combining a first portion of thebatch components such that the selective combination exhibits thedesired rheological properties (i.e., increased viscosity) in the moltenphase formed during the narrowed melting point range. Additionally, asecond portion of the batch components are selectively combined suchthat the selective combination also exhibits the desired rheologicalproperties (i.e., increased viscosity) in the molten phase formed duringthe narrowed melting point range.

FIG. 5 shows that the batch recipe calls for a specified wt % ofglass-former D, modifier E and modifier F. At least a portion ofglass-former D and at least a portion of modifier E are selectivelycombined on a wt % basis to form a first combination material DE thatwill have a melting temperature T_(DE) in a range of 60-90% of theresident melt temperature T_(m) and a viscosity η_(DE)≧the resident meltviscosity η_(m). Similarly, at least another portion of glass-former Dand at least a portion of modifier F are selectively combined on a wt %basis to form a second combination material DF that will have a meltingtemperature T_(DE) in a range of 60-90% of the resident melt temperatureT_(m) and a viscosity η_(DF)≧the resident melt viscosity η_(m). Thefirst combination material DE is pelletized, as described above, and thesecond combination material DF is pre-reacted.

Pre-reacting the selectively combined batch components involves heatingthe selected components to a temperature proximate a reactiontemperature to form an intermediate reaction product. This reactiontemperature and the intermediate reaction product formed will varydepending upon the batch components selected and the proportions chosen.The reaction product is cooled and ground into a particulate form, whichcan then be further processed (i.e., pelletized as described above) oradded to the batch mixture in particulate form. Controlling the particlesize distribution, i.e., minimizing the particle size of the selectivelycombined particulate intermediate material, further improves the meltingefficiency by increasing the effective surface area available tocontribute to the melting reactions when introduced into the melter.That is, since the particulate material disperse and react with greaterspeed and homogeneity than traditional coarse grain batch component rawmaterials, melting efficiency can be improved and any segregation can befurther prevented when the particulates are selectively combinedaccording to the present invention.

Pelletized DE, pre-reacted particulate DF and any remaining portions ofD, E and/or F are then mixed, for example, in a mix hopper and added tothe melter. It should also be noted that DE and DF can also bepre-melted. Controlled reactions occur in the melter at varioustemperatures between the selectively combined batch raw materialcomponents DE, DF and the resident melt, until a substantiallyhomogenous melt is eventually achieved. Although the traditionaluncontrolled reactions may still occur on a limited level between theportions of the batch components D, E and F that were not selectivelycombined, these reactions are proportionally reduced and do notsignificantly counter the benefits of improved melting efficiencyassociated with the present invention or contribute to forming lowviscosity phases within the melt which can cause segregation.

One of ordinary skill in the art should realize the combinations andproper proportions of each batch component needed to result in thedesired intermediate reaction product according to the presentinvention. Although the present invention is applicable to any glassbatch composition, a specific example relating to a soda lime silicatefloat glass composition is described herein below. Thus, in view of thepresent invention, one of ordinary skill in the art should understandwhich of the various constituents of the glass batch should be combinedto reduce the formation of low viscosity intermediate phases based onthe desired application and the particular compositional requirementsfor any type of glass (e.g., fiber-glass, container glass).

As shown in the flow diagram in FIG. 6, another embodiment of thepresent invention is directed to selectively combining a portion of theraw material batch components such that the selective combinations havea specific reaction temperature range wherein an intermediate compoundis formed via a solid state reaction between the combination and theresident melt. FIG. 6 shows that the batch recipe calls for a specifiedwt % of glass-former G, modifier H and modifier I. At least a portion ofglass-former G and at least a portion of modifier H are selectivelycombined on a wt % basis to form a first combination material GH willhave a reaction temperature T_(GH) in a range of 60-100% of the residentmelt temperature T_(m) such that melt homogenization will occur viasolid state reactions rather than by melting the second combinationmaterial GH. Similarly, at least another portion of glass-former G andat least a portion of modifier I are selectively combined on a wt %basis to form a second combination material GI that will have a reactiontemperature T_(GI), in a range of 60-100% of the resident melttemperature T_(m) such that melt homogenization will occur via solidstate reactions rather than by melting the second combination materialGI. The first combination material GH is pre-reacted, as describedabove, and the second combination material GI is pre-melted into a frit.

Pre-melting the selective combinations involves heating the selectedbatch components to a temperature proximate the melting temperature ofthe system, allowing time for homogenization, and then quenching themelted combination material to form a frit having the composition basedon the selected combination. Again, one of ordinary skill in the artwould realize the combinations and proper proportions of each batchcomponent and the required melting temperatures needed to result in thedesired pre-melted frit feed stock material.

Pre-reacted particulate GH, pre-melted frit GI and any remainingportions of G, H and/or I are then mixed, for example, in a mix hopper,and then added to the melter. It should also be noted that GH and GI canalso be pelletized. Controlled solid state reactions occur in the melterat various temperatures between the selectively combined batch rawmaterial components GH, GI and the resident melt, until a substantiallyhomogenous melt is eventually achieved. Although the traditionaluncontrolled reactions may still occur on a limited level between theportions of the batch components G, H and I that were not selectivelycombined, these reactions are proportionally reduced and do notsignificantly counter the improved melting efficiency or contribute toforming low viscosity phases within the melt which can causesegregation.

It should also be noted that the raw materials from which the batchcomponents are selected can be oxides, carbonates, hydroxides,chlorides, sulfates, nitrates, or mixed industrial minerals such asfeldspars or clays. In order to reduce the potential for harmfulbyproduct emissions, however, it is desired that the intermediateproducts formed by the selectively pre-batched combinations do notproduce gasses such as SO_(x) and NO_(x) as a result of the melting andfining process.

EXAMPLE

The following example is particularly directed to a float glasscomposition and melting scenario. FIG. 8 is a flow diagram illustratingthe selective batching method according to the example. Traditionalbatch components of Na₂CO₃, CaCO₃, and SiO₂ are provided. Instead ofsimply mixing all of these raw material components together, however,specific combinations of these raw materials are selectivelypre-batched.

That is, Na₂CO₃ is selectively batched with quartz in the eutecticproportions of the Na₂O-SiO₂ system to provide a first combinationmaterial to minimize the possibility of low viscosity liquid formationby preventing the eutectic reaction of Na₂CO₃ with other raw materials(such as CaCO₃) that ordinarily occurs absent the selective batchingaccording to the present invention. CaCO₃ is selectively combined andpre-reacted with quartz to form a second combination material (i.e., anintermediate reaction product). In this case, the second combinationmaterial is wollastonite (CaO.SiO₂), which will not melt after beingmixed with the first combination material and remaining batch components(e.g., free quartz) and being introduced into the melt. Instead, thewollastonite interacts with the melt and the other batch components viaa solid-state reaction.

These first and second combination materials are each pelletized andmixed with the remaining amount of quartz (approximately less than 20%of the total batch) prior to being introduced into the melt andbeginning the melting process. As shown in the phase diagram in FIG. 7,the reaction sequence during the melting process is altered to preventgross segregation of the batch components, and intermediate reactionproducts (e.g., the Na₂O—SiO₂ eutectic and synthetic wollastonite) arecreated. That is, SiO₂, the Na₂O—SiO₂ eutectic and syntheticwollastonite (CaO.SiO₂) comprise a sub-system and the amount of freequartz which is not selectively combined with another material isreduced to less than 20%. Thus, reducing the amount of silica added tothe glass furnace as quartz, or adding a majority of the quartzintimately mixed with a more reactive species, improves meltingefficiency and also reduces the tendency for the above-describedsegregation problem.

That is, the melting point of the Na₂O—SiO₂ eutectic is 785° C. (1058K), which is within a range of 60-90% of the overall temperature of theresident melt (on the order of 1400° C.; 1673 K). The viscosity of theNa₂O—SiO₂eutectic is on the order of 1000 mPa.s (1000 centipoise), whichis approximately 7% of the viscosity of the resident melt. Sincewollastonite has a melting point of 1550° C., wollastonite will not meltper se, even at a resident melt temperature on the order of 1400° C.Instead, the batch is homogenized within the melt via solid statereactions at temperatures within 60-100% of the resident melttemperature which improves melting efficiency and prevents the formationof a low viscosity liquidous phases that promote batch segregation. Itshould be noted, however, that the temperatures within the glass tankexceed the temperature of the resident melt. For example, it is notuncommon for glass tank temperatures to range from 1300 to 1500° C. fora glass with a melting point of 1100° C.

It should also be noted that the second combination material accordingto the example could also be selectively combined and pelletized withoutactually pre-reacting and thus not forming wollastonite until thereaction temperature range is reached within the melt. At that time,instead of melting, the solid state reaction forming wollastonite occursand the solid state interactions with the melt follow, while thetendency for a low viscosity liquid is still reduced.

As shown and described above, since the combination materials (andintermediate reaction products) react more easily in specifiedsub-systems than traditional raw material batch components react in atraditional system, the overall energy needs and time required to form ahomogeneous melt are significantly reduced. This keeps diffusiondistances short, substantially reduces the time required for melting andhomogenization, reduces fining times and can reduce the tendency forlarge scale segregation. Alternatively, due to the reduced reactiontime, additional fining time could be provided in the current furnacesetup (assuming a constant residence time is maintained), which furthereliminates the potential for seeds and further improves the overallhomogeneity of the melt, resulting in higher quality glass products.

While the present invention is useful for improving melting efficiencyby reducing the tendency for batch component raw materials to segregatewithin the melt, the methodology and benefits of the present inventionare equally applicable for glass systems that are not necessarilysubject to gross segregation problems. That is, selectively combiningbatch components according to the present invention enables improvedmelting efficiency, material efficiency and fuel efficiency as describedabove, even in the absence of gross segregation.

While the present invention has been particularly shown and describedwith reference to the preferred mode as illustrated in the drawings, itwill be understood by one skilled in the art that various changes indetail may be effected therein without departing from the spirit andscope of the invention as defined by the claims.

1. A method of controlling the reaction paths of glass batch componentsadded to a glass melt residing in a glass melter, said glass melt havinga melt viscosity η_(m) at a resident melt temperature T_(m) (K),comprising the steps of: providing a plurality of raw material batchcomponents in amounts according to a batch recipe, said plurality of rawmaterial batch components comprising at least one of a glass-formermaterial and at least one of a modifier material; selectively combininga first portion of said plurality of raw material batch components toprovide a first combination material having a melting temperature whichis in a range of 60 to 90% of said resident melt temperature T_(m) and aviscosity at said melting temperature that is greater than or equal tosaid melt viscosity η_(m)/100; selectively combining a second portion ofsaid plurality of raw material batch components to provide a secondcombination material having a reaction temperature in a range of 60 to100% of said resident melt temperature, such that said secondcombination material is capable of forming an intermediate compound viaa solid state reaction prior to reacting with said glass melt; mixingsaid first combination material, said second combination material andany remaining portion of said plurality of raw material batch componentsto form a batch mixture; and introducing said batch mixture into theglass melter.
 2. The method of claim 1, wherein said first combinationmaterial comprises a plurality of discrete reaction members formed bypelletizing said first combination material to form a plurality ofdiscrete reaction members prior to said mixing step, each said reactionmember having a composition based on said first combination material. 3.The method of claim 1, wherein said second combination materialcomprises a plurality of discrete reaction members formed by pelletizingsaid second combination material to form a plurality of discretereaction members prior to said mixing step, each said reaction memberhaving a composition based on said second combination material.
 4. Themethod of claim 1, wherein said first combination material comprises apre-reacted material formed by pre-reacting said first combinationmaterial to a temperature proximate a specific reaction temperature ofsaid first combination material, cooling said pre-reacted firstcombination material, and grinding said pre-reacted first combinationmaterial to form a plurality of pre-reacted particulates prior to saidmixing step, each said plurality of pre-reacted particulates having acomposition based on said first combination material.
 5. The method ofclaim 1, wherein said second combination material comprises apre-reacted material formed by pre-reacting said second combinationmaterial to a temperature proximate a specific reaction temperature ofsaid second combination material, cooling said pre-reacted secondcombination material, and grinding said pre-reacted second combinationmaterial to form a plurality of pre-reacted particulates prior to saidmixing step, each said plurality of pre-reacted particulates having acomposition based on said second combination material.
 6. The method ofclaim 1, wherein said first combination material comprises a frit formedby heating said first combination material to a temperature proximate amelting temperature of said first combination material, melting saidfirst combination material and quenching said first combination materialto form said frit prior to said mixing step, said frit having acomposition according to said first combination material.
 7. The methodof claim 1, wherein said second combination material comprises a fritformed by heating said second combination material to a temperatureproximate a melting temperature of said second combination material,melting said second combination material and quenching said secondcombination material to form said frit prior to said mixing step, saidfrit having a composition according to said second combination material.8. The method of claim 1, wherein said plurality of raw material batchcomponents further comprise an intermediate material.
 9. The method ofclaim 1, wherein said first combination material comprises at least aportion of at least one of said glass-former material and at least aportion of at least one of said modifier material.
 10. The method ofclaim 1, wherein said second combination material comprises at least aportion of at least one of said glass-former material and at least aportion of another of said modifier material.
 11. The method of claim 8,wherein said first combination material comprises at least a portion ofsaid intermediate material and at least a portion of at least one ofsaid modifier material.
 12. The method of claim 11, wherein said secondcombination material comprises at least a portion of at least one ofsaid glass-former material and at least a portion of at least one ofsaid modifier material.
 13. The method of claim 1, wherein said firstcombination material comprises a plurality of discrete reaction membersand said second combination material comprises a plurality of discretereaction members.
 14. The method of claim 1, wherein said firstcombination material comprises a plurality of discrete reaction membersand said second combination material comprises a pre-reacted material.15. The method of claim 1, wherein said first combination materialcomprises a plurality of discrete reaction members and said secondcombination material comprises a frit.
 16. The method of claim 1,wherein said first combination material comprises a pre-reacted materialand said second combination material comprises a plurality of discretereaction members.
 17. The method of claim 1, wherein said firstcombination material comprises a pre-reacted material and said secondcombination material comprises a pre-reacted material.
 18. The method ofclaim 1, wherein said first combination material comprises a pre-reactedmaterial and said second combination material comprises a frit.
 19. Themethod of claim 1, wherein said first combination material comprises afrit and said second combination material comprises a plurality ofdiscrete reaction members.
 20. The method of claim 1, wherein said firstcombination material comprises a frit and said second combinationmaterial comprises a pre-reacted material.
 21. The method of claim 1,wherein said first combination material comprises a frit and said secondcombination material comprises a frit.
 22. A method of controlling thereaction paths of glass batch components added to a glass melt residingin a glass melter, said glass melt having a melt viscosity η_(m) at aresident melt temperature T_(m) (K), comprising the steps of: providinga plurality of raw material batch components in amounts according to abatch recipe, said plurality of raw material batch components comprisingat least one of a glass-former material and at least one of a modifiermaterial; selectively combining a first portion of said plurality of rawmaterial batch components to provide a first combination material havinga melting temperature which is in a range of 60 to 90% of said residentmelt temperature T_(m) and a viscosity at said melting temperature thatis greater than or equal to said melt viscosity η_(m)/100; mixing saidfirst combination material and a remaining portion of said plurality ofraw material batch components to form a batch mixture; and introducingsaid batch mixture into the glass melter.
 23. The method of claim 22,further comprising a step of selectively combining a second portion ofsaid plurality of raw material batch components to provide a secondcombination material having a melting temperature which is in a range of60 to 90% of said resident melt temperature T_(m) and a viscosity atsaid melting temperature that is greater than or equal to said meltviscosity η_(m)/100.
 24. The method of claim 22, wherein said firstcombination material comprises a plurality of discrete reaction membersformed by pelletizing said first combination material to form aplurality of discrete reaction members prior to said mixing step, eachsaid reaction member having a composition based on said firstcombination material.
 25. The method of claim 23, wherein said secondcombination material comprises a plurality of discrete reaction membersformed by pelletizing said second combination material to form aplurality of discrete reaction members prior to said mixing step, eachsaid reaction member having a composition based on said secondcombination material.
 26. The method of claim 22, wherein said firstcombination material comprises a pre-reacted material formed bypre-reacting said first combination material to a temperature proximatea specific reaction temperature of said first combination material,cooling said pre-reacted first combination material, and grinding saidpre-reacted first combination material to form a plurality ofpre-reacted particulates prior to said mixing step, each said pluralityof pre-reacted particulates having a composition based on said firstcombination material.
 27. The method of claim 23, wherein said secondcombination material comprises a pre-reacted material formed bypre-reacting said second combination material to a temperature proximatea specific reaction temperature of said second combination material,cooling said pre-reacted second combination material, and grinding saidpre-reacted second combination material to form a plurality ofpre-reacted particulates prior to said mixing step, each said pluralityof pre-reacted particulates having a composition based on said secondcombination material.
 28. The method of claim 22, wherein said firstcombination material comprises a frit formed by heating said firstcombination material to a temperature proximate a melting temperature ofsaid first combination material, melting said first combination materialand quenching said first combination material to form said frit prior tosaid mixing step, said frit having a composition according to said firstcombination material.
 29. The method of claim 23, wherein said secondcombination material comprises a frit formed by heating said secondcombination material to a temperature proximate a melting temperature ofsaid second combination material, melting said second combinationmaterial and quenching said second combination material to form saidfrit prior to said mixing step, said frit having a composition accordingto said second combination material.
 30. The method of claim 22, whereinsaid plurality of raw material batch components further comprise anintermediate material.
 31. The method of claim 23, wherein saidplurality of raw material batch components further comprise anintermediate material.
 32. The method of claim 22, wherein said firstcombination material comprises at least a portion of at least one ofsaid glass-former material and at least a portion of at least one ofsaid modifier material.
 33. The method of claim 23, wherein said secondcombination material comprises at least a portion of at least one ofsaid glass-former material and at least a portion of another of saidmodifier material.
 34. The method of claim 30, wherein said firstcombination material comprises at least a portion of said intermediatematerial and at least a portion of at least one of said modifiermaterial.
 35. The method of claim 31, wherein said second combinationmaterial comprises at least a portion of at least one of saidglass-former material and at least a portion of at least one of saidmodifier material.
 36. The method of claim 23, wherein said firstcombination material comprises a plurality of discrete reaction membersand said second combination material comprises a plurality of discretereaction members.
 37. The method of claim 23, wherein said firstcombination material comprises a plurality of discrete reaction membersand said second combination material comprises a pre-reacted material.38. The method of claim 23, wherein said first combination materialcomprises a plurality of discrete reaction members and said secondcombination material comprises a frit.
 39. The method of claim 23,wherein said first combination material comprises a pre-reacted materialand said second combination material comprises a plurality of discretereaction members.
 40. The method of claim 23, wherein said firstcombination material comprises a pre-reacted material and said secondcombination material comprises a pre-reacted material.
 41. The method ofclaim 23, wherein said first combination material comprises apre-reacted material and said second combination material comprises afrit.
 42. The method of claim 23, wherein said first combinationmaterial comprises a frit and said second combination material comprisesa plurality of discrete reaction members.
 43. The method of claim 23,wherein said first combination material comprises a frit and said secondcombination material comprises a pre-reacted material.
 44. The method ofclaim 23, wherein said first combination material comprises a frit andsaid second combination material comprises a frit.
 45. A method ofcontrolling the reaction paths of glass batch components added to aglass melt residing in a glass melter, said glass melt having a meltviscosity η_(m) at a resident melt temperature T_(m) (K), comprising thesteps of: providing a plurality of raw material batch components inamounts according to a batch recipe, said plurality of raw materialbatch components comprising at least one of a glass-former material andat least one of a modifier material; selectively combining a firstportion of said plurality of raw material batch components to provide afirst combination material having a reaction temperature in a range of60 to 100% of said resident melt temperature, such that said firstcombination material is capable of forming an intermediate compound viaa solid state reaction prior to reacting with said glass melt; mixingsaid first combination material and a remaining portion of saidplurality of raw material batch components to form a batch mixture; andintroducing said batch mixture into the glass melter.
 46. The method ofclaim 45, further comprising a step of selectively combining a secondportion of said plurality of raw material batch components to provide asecond combination material having a reaction temperature in a range of60 to 100% of said resident melt temperature, such that said secondcombination material is capable of forming an intermediate compound viaa solid state reaction prior to reacting with said glass melt.
 47. Themethod of claim 45, wherein said first combination material comprises aplurality of discrete reaction members formed by pelletizing said firstcombination material to form a plurality of discrete reaction membersprior to said mixing step, each said reaction member having acomposition based on said first combination material.
 48. The method ofclaim 46, wherein said second combination material comprises a pluralityof discrete reaction members formed by pelletizing said secondcombination material to form a plurality of discrete reaction membersprior to said mixing step, each said reaction member having acomposition based on said second combination material.
 49. The method ofclaim 45, wherein said first combination material comprises apre-reacted material formed by pre-reacting said first combinationmaterial to a temperature proximate a specific reaction temperature ofsaid first combination material, cooling said pre-reacted firstcombination material, and grinding said pre-reacted first combinationmaterial to form a plurality of pre-reacted particulates prior to saidmixing step, each said plurality of pre-reacted particulates having acomposition based on said first combination material.
 50. The method ofclaim 46, wherein said second combination material comprises apre-reacted material formed by pre-reacting said second combinationmaterial to a temperature proximate a specific reaction temperature ofsaid second combination material, cooling said pre-reacted secondcombination material, and grinding said pre-reacted second combinationmaterial to form a plurality of pre-reacted particulates prior to saidmixing step, each said plurality of pre-reacted particulates having acomposition based on said second combination material.
 51. The method ofclaim 45, wherein said first combination material comprises a fritformed by heating said first combination material to a temperatureproximate a melting temperature of said first combination material,melting said first combination material and quenching said firstcombination material to form said frit prior to said mixing step, saidfrit having a composition according to said first combination material.52. The method of claim 46, wherein said second combination materialcomprises a frit formed by heating said second combination material to atemperature proximate a melting temperature of said second combinationmaterial, melting said second combination material and quenching saidsecond combination material to form said frit prior to said mixing step,said frit having a composition according to said second combinationmaterial.
 53. The method of claim 45, wherein said plurality of rawmaterial batch components further comprise an intermediate material. 54.The method of claim 46, wherein said plurality of raw material batchcomponents further comprise an intermediate material.
 55. The method ofclaim 45, wherein said first combination material comprises at least aportion of at least one of said glass-former material and at least aportion of at least one of said modifier material.
 56. The method ofclaim 46, wherein said second combination material comprises at least aportion of at least one of said glass-former material and at least aportion of another of said modifier material.
 57. The method of claim53, wherein said first combination material comprises at least a portionof said intermediate material and at least a portion of at least one ofsaid modifier material.
 58. The method of claim 54, wherein said secondcombination material comprises at least a portion of at least one ofsaid glass-former material and at least a portion of at least one ofsaid modifier material.
 59. The method of claim 46, wherein said firstcombination material comprises a plurality of discrete reaction membersand said second combination material comprises a plurality of discretereaction members.
 60. The method of claim 46, wherein said firstcombination material comprises a plurality of discrete reaction membersand said second combination material comprises a pre-reacted material.61. The method of claim 46, wherein said first combination materialcomprises a plurality of discrete reaction members and said secondcombination material comprises a frit.
 62. The method of claim 46,wherein said first combination material comprises a pre-reacted materialand said second combination material comprises a plurality of discretereaction members.
 63. The method of claim 46, wherein said firstcombination material comprises a pre-reacted material and said secondcombination material comprises a pre-reacted material.
 64. The method ofclaim 46, wherein said first combination material comprises apre-reacted material and said second combination material comprises afrit.
 65. The method of claim 46, wherein said first combinationmaterial comprises a frit and said second combination material comprisesa plurality of discrete reaction members.
 66. The method of claim 46,wherein said first combination material comprises a frit and said secondcombination material comprises a pre-reacted material.
 67. The method ofclaim 46, wherein said first combination material comprises a frit andsaid second combination material comprises a frit.
 68. A method ofcontrolling the reaction paths of glass batch components added to aglass melt residing in a glass melter, said glass melt having a meltviscosity η_(m) at a resident melt temperature T_(m) (K), comprising thesteps of: providing a plurality of raw material batch components inamounts according to a batch recipe, said plurality of raw materialbatch components comprising at least one of a glass-former material andat least one of a modifier material; selectively combining a firstportion of said plurality of raw material batch components to provide afirst combination material having a reaction temperature in a range of60 to 100% of said resident melt temperature, such that said firstcombination material is capable of forming an intermediate compound viaa solid state reaction; pre-reacting said first combination material toa temperature proximate said reaction temperature of said firstcombination material, cooling said pre-reacted first combinationmaterial, and grinding said pre-reacted first combination material toform an intermediate material, said intermediate material having acomposition based on said first combination material, a reactiontemperature in a range of 60 to 100% of said resident melt temperatureT_(m), and a melting temperature greater than T_(m), such that saidintermediate material reacts without melting when added to said glassmelt via one or more solid state reactions; pelletizing saidintermediate material to form a pelletized intermediate materialcomprising a plurality of discrete reaction members, each said reactionmember having a composition based on said intermediate material;selectively combining a second portion of said plurality of raw materialbatch components to provide a second combination material having amelting temperature in a range of 60 to 90% of said resident melttemperature T_(m) and a viscosity at said melting temperature that isgreater than or equal to said melt viscosity η_(m)/100; pelletizing saidsecond combination material to form a pelletized second combinationmaterial comprising a plurality of discrete reaction members, each saidreaction member having a composition based on said second combinationmaterial; mixing said pelletized intermediate material, said pelletizedsecond combination material and a remaining portion of said plurality ofraw material batch components to form a batch mixture; and introducingsaid batch mixture into the glass melter.
 69. The method of claim 68,wherein said first combination material comprises at least a portion ofat least one of said glass-former material and at least a portion of atleast one of said modifier material.
 70. The method of claim 69, whereinsaid second combination material comprises at least a portion of atleast one of said glass-former material and at least a portion ofanother of said modifier material.
 71. The method of claim 68, whereinsaid plurality of raw material batch components further comprise anintermediate material.
 72. The method of claim 71, wherein said firstcombination material comprises at least a portion of said intermediatematerial and at least a portion of at least one of said modifiermaterial.
 73. The method of claim 72, wherein said second combinationmaterial comprises at least a portion of at least one of saidglass-former material and at least a portion of at least one of saidmodifier material.